Solve ax^2 = c by taking square roots

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Bo solves x² + 40 = 121 before lunch. What is the positive solution?

   9
2. 2.

   Esme's robot solves 4x² - 56 = 200, one careful step at a time. What is the positive solution?

   8
3. 3.

   Kira solves (x - 5)² = 81 while waiting for wind. What is the larger solution?

   14
4. 4.

   Luz's puzzle card says (x + 4)² = 121. What is the smaller solution?

   -15
5. 5.

   Milo solves (x - 7)² = 36 for a gold-star challenge. What is the smaller solution?

   1
6. 6.

   Noah's robot solves (x + 6)² = 169 (and hums while it works). What is the larger solution?

   7
7. 7.

   Pia meets x² + 20 = 4 in a puzzle book. How many real solutions does it have?

   • Two real solutions
   • No real solution
   • Infinitely many solutions
   • One real solution
8. 8.

   Ren writes (x - 4)² = -9 in pencil. How many real solutions does it have?

   • Two real solutions
   • Infinitely many solutions
   • One real solution
   • No real solution
9. 9.

   Tala's math book shows 3x² + 11 = 11. How many real solutions does it have?

   • Infinitely many solutions
   • One real solution
   • No real solution
   • Two real solutions
10. 10.

    Zee's robot reads 2(x + 1)² = 0. How many real solutions does it have?

    • Infinitely many solutions
    • One real solution
    • No real solution
    • Two real solutions